• 한국지하수토양환경학회지:지하수토양환경
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• 제25권1호
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• pp.84-94
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• 2020

Jeju Island is seeking reliable ways to secure alternative water resources using rainwater in order to conserve and manage its groundwater as sustainable water resources. The purpose of this study is to investigate the rainwater storage capability of small-size storage facilities installed at farmhouses in Uigwi and Wimi of Namwon-eup region. The rainwater outflows from the storage facilities in rain events were analyzed. The appropriate size of rainwater utilizing facilities are suggested to be about 5,800 ㎥ in Uigwi area and 4,900 ㎥ in Wimi area based on the calculation from the rainfall frequency and runoff amounts. If those facilities are put into operation in Uigwi and Wimi area, it is estimated approximately 32.3 and 11.5% of total agricultural water can be supplied by the facilities. Wimi area showed low rainwater usage because of less number of facilities relative to the size of farm areas and less intensive underground water usage. It is analyzed that more than 55% of agricultural water can be supplied by rainwater if 70 facilities without the rainwater facilities are connected to the rainwater utilizing facilities.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.293-298
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• 2005

We calculate the coordinates of an axisymmetric nozzle with a central body. This nozzle ensures a transonic flow with a plane sound surface, which is orthogonal to the symmetry axis and has a wall kink at the sonic point, The Chaplygin transformation in the subsonic part of the flow leads the Dirichlet problem for a system of nonlinear equations. The definition domain of the solution in the velocity-hodograph plane is taken as a rectangle. This enables one to obtain the nozzle with a monotonic distribution of velocity along its subsonic part. In the nonlinear differential equation, the linear Chaplygin operator for plane flows is separated, which allows the iterative calculation of the solution. The supersonic part of the nozzle is calculated under the assumption that the flow at the nozzle exit is uniform and parallel to the symmetry axis; i.e., the supersonic jet outflows to the submerged space with the same pressure. The calculation is performed by the characteristic method. The exact solution of Tricomi equation for near-sonic flows with the straight sonic line is used to 'move away' the sound plane. The velocity distribution alone the supersonic part of the nozzle is also monotonic, which ensures the absence of the boundary-layer separation and, therefore, the adequacy of the ideal-gas model. calculations show that the flow in the supersonic part of the nozzle is continuous (compression shocks are absent)

• Water Engineering Research
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• 제5권1호
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• pp.17-36
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• 2004

This paper evaluated the water resources aspect of the operating results of the Daecheong Multipurpose Dam for the last 21 years. The elements that were evaluated included the amount of water supply from the dam. volume of outflow from the regulating dam, changes in the runoff volume at the dam site and downstream, and variations in the water supply capacity of the Daecheong Multipurpose Dam and the Geum River Barrage Dam situated in the estuary. The rainfall-runoff model was used to evaluate the changes in the runoff volume, and the water balance analysis system was used to evaluate the variations in the dams'water supply capacities. The volume of domestic and industrial water supply from the Daecheong Multipurpose Dam increased to 6.1 times for the last 21 years from 61${\times}$$10^6$$m^3$ in 1981 to 375${\times}$$10^6$$m^3$in 2001. The rate of outflow to inflow of the Daecheong Dam was analyzed 1.30 times in dry season, 1.12 times in semi-dry season, and 0.90 times in rainy season. The volume of inflow to the Geum River Barrage Dam down- stream after the dam's construction increased to 1.25 times in dry season and 1.02 times in semi-dry season and decreased to 0.94 times in rainy season. The water supply capacity of the estuary barrage dam almost did not change in cases with or without the Daecheong Multipurpose Dam, but storages were largely affected by the outflows of the Daecheong Multipurpose Dam.

• 한국방재학회 논문집
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• 제10권6호
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• pp.99-108
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• 2010

본 연구에서는 네 개의 도로가 서로 대칭으로 연결된 교차로 근처 및 내에서의 흐름 특성에 대한 수치적 분석을 수행하였으며, 적용된 수치모형은 2차원 well-balanced HLLC 유한체적모형이다. 모의 및 분석결과 본 연구에서 적용된 모형은 유입유량 및 수로경사 조건에 따라 도로 교차로에서 변화되는 복잡한 수면양상을 비교적 잘 모의하는 것으로 나타났다. 또한 도로 교차로 내에서의 시간적 및 공간적 수심변화와 두 개의 하류경계에서의 유출유량에 대한 모의결과는 측정결과와 비교적 잘 일치하였다.

• Journal of Astronomy and Space Sciences
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• 제29권1호
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• pp.47-49
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• 2012

Massive binary stars lose mass by two mechanisms: jet-driven mass loss during periods of active mass transfer and by wind-driven mass loss. Beta Lyrae is an eclipsing, semi-detached binary whose state of active mass transfer provides a unique opportunity to study how the evolution of binary systems is affected by jet-driven mass loss. Roche lobe overflow from the primary star feeds the thick accretion disk which almost completely obscures the mass-gaining star. A hot spot predicted to be on the edge of the accretion disk may be the source of beta Lyrae's bipolar outflows. I present results from spectropolarimetric data taken with the University of Wisconsin's Half-Wave Spectropolarimeter and the Flower and Cook Observatory's photoelastic modulating polarimeter instrument which have implications for our current understanding of the system's disk geometry. Using broadband polarimetric analysis, I derive new information about the structure of the disk and the presence and location of a hot spot. These results place constraints on the geometrical distribution of material in beta Lyrae and can help quantify the amount of mass lost from massive interacting binary systems during phases of mass transfer and jet-driven mass loss.

• 자원ㆍ환경경제연구
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• 제21권3호
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• pp.519-542
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• 2012

본 논문은 EU ETS 기간 전과 후를 비교함으로써 탄소누출이 일어났는가를 실증적으로 분석하였다. 해외직접투자를 탄소누출의 지표로 활용하여 EU 11개국을 대상으로 한 1995년부터 2009년까지의 패널데이터를 이용하여 생산비용과 환경비용과의 패널 분석을 하였다. 시장 추구형 해외직접효과도 아울러 고려하여 해외시장잠재력도 아울러 고려하였다. 본 분석에 의하면 제조업을 대상으로 한 일부모형에서 탄소누출이 확인되었다. 하지만 다양한 모형에서 일관되게 확인되지 않아서 EU 배출권거래제를 전후하여 탄소누출이 뚜렷하게 일어났다고 단정하기는 힘들다. 비교적 데이터의 시계열이 짧음에도 불구하고 일부모형에서 탄소누출이 검증되었다는 사실을 볼 때 향후 국내 배출권거래제 도입시 우리나라도 탄소누출의 가능성을 염두에 두고 배출권거래제 제도를 설계해야 할 것이다.

• 천문학회보
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• 제39권2호
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• pp.113.2-113.2
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• 2014

Methanol masers are divided into two classes, I and II. Class II methanol masers trace the disk-outflow systems of massive young stellar objects (YSOs), while class I methanol masers appear to trace the interaction regions of outflows with the ambient molecular gas. Class II masers have been extensively studied by single dishes, connected arrays, and VLBIs. Meanwhile, class I masers have been much less studied. They have not been detected by any VLBI facility. Thus they have been believed to have more extended structures than class II masers. We made fringe surveys of 44GHz class I methanol maser emission towards more than 150 massive YSOs with flux densities >10 Jy using the Korean VLBI Network (KVN), and detected fringes in ~10% of the sources. We performed follow-up imaging observations of the detected maser sources with KVN and KVN+VERA (KaVA). The observations aim to investigate the distribution and kinematics of 44GHz methanol maser features in each source at milli-arcsecond resolutions, and to understand what they trace. In this talk we will present the fringe survey and imaging results and our plans for further studies. Additionally, we will also introduce the preliminary results of single-dish polarization observations of water and class I methanol masers.

• 한국해양공학회지
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• 제16권5호
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• pp.15-20
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• 2002

In this research, the finite difference lattice Boltzmann method(FDLBM) is used to analyze gravity currents in the lock exchange configuration that occur in many natural and man-made situations. At a lock those are seen when a gate is suddenly opened, and, in the atmosphere, when the thunderstorm outflows make a cold front. At estuaries in the ocean, the phenomenon is found between fresh water from a river and salt water in the sea. Since such interesting phenomena were recognized, pioneers have challenged to make them clear by conducing both experiments and analysis. Most of them were about the currents of liquid or Boussinesq fluids, which are assumed as incompressible. Otherwise, the difference in density of two fluids is small. The finite difference lattice Boltzmann method has been a powerful tool to simulate the flow of compressible fluids. Also, numerical predictions using FDLBM to clarify the gravity currents of compressible fluids exhibit all features, but typically observed in experimental flows near the gravity current head, including the lobe-and-cleft structure at the leading edge.

• 정보학연구
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• 제4권3호
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• pp.19-34
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• 2001

본 연구는 배당의 형태에 따라 개인투자자들이 배당세를 인식하여 투자가치를 평가하는가를 검증하는 것이 목적이다. 현금배당의 경우에는 기업의 현금유출이 발생하지만 주식배당의 경우에는 기업의 순장부가치에 변동을 초래하지 않는다. 개인투자자들이 배당에 대해 배당세를 인식하고 투자가치를 평가한다면 순장부가치에서 납입자본과 이익잉여금의 가치를 다르게 인식하게 된다. 검증결과 현금배당의 경우에는 배당세를 인식하여 순장부가치를 평가하지만 주식배당의 경우에는 배당세를 인식하는 뚜렷한 증거를 발견할 수 없었다. 또한 순이익에 대해서는 배당의 형태에 관계없이 배당세를 인식하지 않는 것으로 나타났다. 본 연구의 결과로 볼 때 공평한 과세를 달성하기 위해서는 배당에 대한 과세뿐만 아니라 자본이득세를 부과함으로써 소득의 형태에 관계없이 동일한 기준으로 과세하는 것이 바람직 할 것으로 보인다.

• 천문학회보
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• 제42권2호
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• pp.44.2-44.2
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• 2017

We obtained near-infrared spectra of 26 SDSS quasars at 0.7${\sim}10^{{\wedge}{10}}M{\odot}$ to critically examine the systematic effects involved with their mass estimations. We find that active galactic nuclei (AGNs) heavier than $10^{{\wedge}{10}}M{\odot}$ often display double-peaked $H{\alpha}$ emission, extremely broad FeII complex emission around MgII, and highly blueshifted and broadened CIV emission. The weight of this evidence, combined with previous studies, cautions against the use of MBH values based on any emission line with a width over 8000 km/s. Also, the MBH estimations are not positively biased along the presence of ionized narrow line outflows, anisotropic radiation, or the use of line FWHM instead of ${\sigma}$ for our sample, and unbiased with variability, scatter in broad line equivalent width, or obscuration for general type-1 quasars. Removing the systematically uncertain MBH values, ${\sim}10^{{\wedge}{10}}M{\odot}$ BHs in 1${\sim}10^{{\wedge}{9.5}}M{\odot}$ BHs, although current observations support they are intrinsically most massive, and overmassive to the host's bulge mass.